How to check a flv or mp4 in a webpage when mouse over?

Use JS,I can check a flash object in a webpage when mouse over it, but how to check a flv or mp4 object when mouse over or out ?

check flash:if(event.target.tagName == "EMBED"),but check flv or mp4 , which tagName I can use ? Thank you very much!

From stackoverflow

• There is a extension on chrome called Flashplus, which does the exact same thing. You can check the code base for that here